Many different designs have been employed to reduce the effect of a low speed impact on a vehicle.
The rear ends of vehicles are designed to meet certain impact standards. Automotive manufacturers and regulators have designed a standard referred to as an “Impact Zone” for determining the crashworthiness and crash resistance of a vehicle in a low speed impact. This zone is changed from time to time as vehicles change and regulations and the test criteria change but, typically, there is a rectangular zone with a predetermined width and height which a vehicle will be tested if it is impacted into “block” of material having those dimensions at a certain speed and the damage caused by the impact. This zone is important for crashworthiness assessment. But, the damage caused in this Impact Zone is also significant in part because insurance companies will vary their prices for insuring of vehicles based on how much damage occurs to a particular vehicle when subjected to an impact in this zone. Minimizing the damage to a vehicle and reducing the repair cost of a vehicle impacted in the Impact Zone is, therefore, important in designing vehicles and parts of vehicles.
Lift gates are a rather large and relatively expensive portion of a crossover or SUV vehicle. In the past, these vehicles were designed to have a bumper area extending out from the vehicle which took much of any impacts before the damage of the impact area approached the actual lift gate area. With advances in vehicle designs, a current trend is to have a flush surface on the front and the rear of a vehicle which incorporates the bumper area into a smooth show surface area of the front and rear vehicle design. Such newer designs have now placed the lift gate in the Impact Zone for many vehicles having such lift gates.
Metal lift gates are typically utilized and while some advances have been made such as replaceable crush zone panels. In modern styled vehicles, the Impact Zone may extend into the structural zone of the vehicle. Additionally, the cost of repairing dents and mechanisms in a lift gate collision has gotten to be excessive. Composite lift gates have been attempted as there are weight and cost savings. But, with such lift gates, the lift gate outer skins and the structural support and reinforcement areas are easily damaged, which often are not easily repairable and or repaintable. Therefore, collision damage of composite lift gates often requires replacement of the entire lift gate.
Accordingly, there exists a need for a composite lift gate which limits the impact damage received during a collision to panels of the lift gate which is able to deform and absorb the impact while protecting the structural components of the lift gate from damage and failure.